Drafting instrument.



P-ATENTED FEB. 12, 1907.

L. R. LOUGHBOROUGH.

DRAFTING INSTRUMENT. APPLIGATION'FILED IBB. zo, 1905.

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LEROY R. LOUGHBOROUGH,

OF ROCHESTER, NEW YORK.

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Specification of Letters Patent.

Patented Feb. 12, 1907.

Application led February 20,1905. Serial No. 246,396.

To @ZZ ZIJ/"wm t may concern:

Be it known that I, LEROY R. Louer-inon- OUGH, a citizen et the UnitedStates, residing at Rochester, in the county of Monroe and State of NewYork, have invented new and useful Improvements in lratting Instruments,of which the following is a speciiication.

This invention relates to an improved instrument suitable f'cr use bydraftsmen, rnechanics, and students of drawing, geometry, and similarsubjects requiring the use of a compass, a square, and a protractor.

The object ci my invention is the provision of a compact, accurate, andinexpensive instrument which combines the advantages of a compass,ruler, and square, and also, preferably, an angle-indicatcr.

In the accompanying drawings, Figure l is a plan view of the instrument.Fig. 2 is an edge view ci its wide end. Fig. 8 is an enlargedcross-section thereof in line 3 3, Fig. l. Fig. e is a fragmentary planview of the instrument, on an enlarged scale, with the center-pin andits adjustable carrier removed. Fig. 5 is a perspective View of thecarrier.

Similar letters of reference indicate corresponding parts throughout theseveral views.

A indicates a ruler forming the main member of the instrument, and B abar extending at right angles to one end of the ruler and forming asquare therewith. These members are made of suitable length and bothhaving the customary graduation marks or lines along' their edges,preferably down to one-eighth cf an inch, as shown.

The main member A is provided with a longitudinal series of holes c,adapted to receive a pencil-point in using the instrument as a compass'for inscribing arcs or circles. holes preferably spaced uniformly andarranged'to coincide with some cr all ci the graduaticns et said member,say the inch,

hall-inch, and quarter-inch marks, as illustrated in the drawings. heseholes may be circular vcr ci other suitable shape; but they arepreferably in the form of transverse slots or keyholes, as shown, thepencil-point being inserted in the round portion et the slot. By thisconstruction the paper or other object upon which a circle is to beinscribed is plainly visible through the slots 'for some distance inadvance of the pencil-point.

At or near the corner ot the square the instrument is provided with aprick-point or center-pin D, upon which it is adapted to be swung inusing the device as a compass. Preferably this pin is adjustablelengthwise ola the main member or scale A and combined with an auxiliaryscale e, divided into iiner graduations than the main scale on saidmember-say sixteenths of an inch-so that it, 'for example, it should bedesired to inscribe a circle having a radius equal to a given number otinches and a fraction of an inch less than the smallest graduationsofthe main scale this can be done by shitting the center pin oppositethe corresponding graduation ci the auxiliary scale. ln the preferredconstruction shown in the drawings the centering-pin consists of apointed screw passing through a longitudinal slotf in the main member iland carried by a plate G, provided centrally at its front edge with apointer g, which traverses the auxiliary scale e, extending along theadjacent edge of said slot. This plate cr carrier has a longitudinalslot g for the passage of a set-screw b, which clamps the plate againstthe face of the member A and engages with a threaded opening 72. termedtherein. The pointer g has a screwthreaded hole g2, which receives thecentering-pin, and the latter is reliably held in place by a lock-nut i.To Airevent accidental turning er twisting oi the plate G, the same isprovided at its rear edge with a downwardlyextending lip cr guide whichenters a longitudinal slot le, termed in the member A.

rlhe keyhole c at the left-hand end of the series is preferably placedclosely to the graduated slot f to pelmit the inscription ol1comparatively small circles. The first or extremo iight-hand graduationot said slot may be marked Zero, as shown, and when the keyholes arearranged in line with the inch, halfinch, and quarter-inch graduationsof the ruler alternate holes numbered 1, 2, 3, ec., beginning with thethird hole from the left-hand. end of the seiies, as best illustrated inFig. l. Ry this arrangement upon adliusting the carrer Gv with itspointer at Zero and inse; ting a pencil-point, for example, in thekeyhole maiked the diameter of the insev 'bed circle will be one inch,while by inserting it in the keyhole marked 2 the diameter of tho circlewill be two inches, and so on. lt it is desired to inscribe a circle'with a I diameter ol one or more inches plus a fraction or an inchsmaller than the distance between successive keyholes, the carrier G isg IOO shifted toward the left as required. By this construction andarrangement the diameter may be ascertained at a glance.

While I prefer to graduate the keyholes and the auxiliary scale e asshown in the drawings, the same may obviously'be Widely varied Withoutdeparting from the scope of the invention.

L indicates a quadrant connecting1 the outer end of the angle-bar B Withthe main membe'r A and bearing suitable degree marks or graduations l,which converge at the vertex of the angle formed by the inner edges ofthe main member A and the bar B. This quadrant serves not only as aprotractor for laying out angles, but is specially useful as anindicator for determining angles already dravvn. In using the instrumentfo'r the lastmentioned purpose the inner edge of the bar B is brought inline With one side of the angle to be ascertained, and the degree of theangle is then read off on the quadrant Where its other side intersectsthe latter.

A supplemental angle-indicator or scale M preferably extends diagonallyfrom the bar B to the main member A on the inner side of the mainangle-indicator L. This supplemental indicator is graduated like themain indicator L and is useful for determining the degree ofcomparatively small angles.

This improved instrument While serving as a ruler, square, andangle-indicator has a large range as a compass. By thus combining thesevarious devices in a single instrument it is very convenient in use andsaves the cost of a set of separate drawing tools or instruments, thusrendering the instrument especially desirable for students.

I claim as my invention*- l 1. An linstrument of the characterdescribed, comprising a ruler provided with a longitudinal series ofholes adapted to receive a marking-point and near one of its ends with alongitudinal slot, a slotted .plate arranged adjacent to said slot, aset-screw for said plate passing through its slot and engaging theruler, and a pin or center carried by the plate and passing through theslot of th ruler, substantially as set forth.

2. An instrument of the character de scribed, comprising a rulerprovided with a longitudinal series of holes adapted to receive amarking-point and near one of its ends With a pair of longitudinalslots, a slotted plate having a guide arranged in one of said slots anda pointer extending across the other slot, a set-screw passing throughthe slot of the plate into the ruler, and a pin or center carried by theplate and passing through the slot 'bridged by said pointer,substantially as set forth.

3. An instrument of the characterl described, comprising a rulerprovided With a main 'scale'or series of graduations, a longitudinalseries of holes coinciding With graduations of said scale, an auxiliaryscale arranged at one end ofV said main scale and having smallergraduations than the same, and a pin or center' adjustably mounted onthe ruler opposite said auxiliary scale, substantially as set forth. p

4. An instrument of the character described, comprising a rulerprovid-ed With a main scale or series of graduations, a longitudinalseries of holes coinciding With graduations of said scale, and alongitudinal slot arranged at one end of the series of holes andprovided along its edge with an auxiliary scale having smallergraduations than said main scale, a plate adjustably secured to theruler adjacent to said slot and having a pointer cooperating With theauxiliary scale, and a pin or center carried by said plate and passingthrough said slot, substantially as set forth. Y

Witness my hand this 9th day of February, 1905.

LEROY R. LOUGHBOROUGH.

Witnesses:

G. B. LoUGHBoRoUGH, C. I-I. VAN NEsT.

